1. B; due to the subject being biology, it isn’t about the mental aspect. Concentration in biology is the amount of a substance in a given area.
2. C; While you may believe it to be B, that isn’t correct answer. Going back to the question, it ask for the point source, which is a main source. Water isn’t a main source, as it carries objects. Chemicals ARE a main source as it was main created from a chemical plant making identifiable.
3. B; Point source pollution is mostly produced by industries and businesses, chemicals and such.
4. B; If I have read that correctly, that being how much isn’t fresh water, then I’m correct as fresh water takes up very little of the ocean compared to salt water
5. C; it’s quite useless knowing what’s in the water compared to where it’s being placed
B; Industrial point source pollution as it being chemicals, which are produced by industries